The above-mentioned patent discloses what is commonly referred to as a bodymaker for forming metal can bodies having an ironed side wall and a unitary inwardly domed end wall.
In the formation of such containers, it is customary to initially draw a flat circular metal disc into a cup shaped article in a cupping machine. The cups are then transferred to the bodymaker of the type disclosed in the above patent wherein the cup is initially redrawn to a reformed cup having a slightly smaller diameter and increased height. The reformed cup is then moved between a punch or ram and a plurality of ironing rings to reduce the side wall thickness of the cup. At the end of the stroke for the ram, the ram cooperates with a doming element to reform the end wall to an inwardly directed dome.
In the formation of containers utilizing a bodymaker of this type, it is absolutely essential to have the cup initially properly aligned with the ram and a cup holder sleeve that supports the cup during the initial redraw operation. Many proposals have been suggested for properly feeding the cups to the bodymaker of the above type and an example of one type of mechanism is disclosed in U.S. Pat. No. 3,715,905. In this patent, the patentee contemplates gravity feeding the cup to a horizontally reciprocating ram and positioning the cup with respect to the ram utilizing a generally U-shaped yoke that has adjustable alignment members associated therewith.
With increased speeds of operation of can making machinery of the above type, it has been difficult to rely upon gravity feeding alone for accurately aligning a cup with a ram on a bodymaker without having some of the cups tilted with respect to the ram thereby resulting in a jam.
More recently the manufacturer of bodymakers of the above type have incorporated another type of cup feeding mechanism wherein the cup is gravity fed along a vertical path laterally offset from the reciprocable ram which is reciprocated along a horizontal axis and a positive cup feeding mechanism is utilized for laterally shifting the cups from the path into alignment with the ram. In this system, the cups again are gravity fed along the path and a flat guide surface is located at the lower end of the path to receive the cups. The cups are then driven along the guide surface through a reciprocating drive member that forces the cups into engagement with a yoke surrounding the path of the ram. The cups are then picked up by the ram and a cup holder which holds the cup in accurate position during the redraw portion of the drawing and ironing operation.
Again such a system has found limited success but has created substantial problems when increased production is attempted. For example, a machine similar to the type disclosed in the above patent has recently been successfully operated at speeds of more than 200 cans per minute. At such speeds, as indicated above, it is totally impractical to rely upon gravity feeding of the cups into accurate alignment with the punch or ram.
When operating at such speeds, and utilizing the gravity feed laterally offset feeding mechanism described above, additional difficulties have been encountered in having the cup prematurely move towards the path for the ram and at times tilt with respect to the axis of the ram thereby resulting in a jam or misfeed.
One of the problems that has been encountered with the gravity feed laterally offset cup feeding mechanism discussed above, is the fact that the weight of the cups in the vertical path will have a tendency to move the lower most cup towards the ram prior to having the drive member or shuttle mechanism positively move such cup. If such movement should occur, the cup may become tilted with respect to its longitudinal axis resulting in a misfeed.